import inspect
from functools import wraps

from dynaconf.utils import recursively_evaluate_lazy_format
from dynaconf.utils import upperfy
from dynaconf.utils.functional import empty
from dynaconf.vendor.box import Box


def evaluate_lazy_format(f):
    """Marks a method on Dynabox instance to
    lazily evaluate LazyFormat objects upon access."""

    @wraps(f)
    def evaluate(dynabox, item, *args, **kwargs):
        value = f(dynabox, item, *args, **kwargs)
        settings = dynabox._box_config["box_settings"]

        if getattr(value, "_dynaconf_lazy_format", None):
            dynabox._box_config[
                f"raw_{item.lower()}"
            ] = f"@{value.formatter.token} {value.value}"

        return recursively_evaluate_lazy_format(value, settings)

    return evaluate


class DynaBox(Box):
    """Specialized Box for dynaconf
    it allows items/attrs to be found both in upper or lower case"""

    @evaluate_lazy_format
    def __getattr__(self, item, *args, **kwargs):
        try:
            return super(DynaBox, self).__getattr__(item, *args, **kwargs)
        except (AttributeError, KeyError):
            n_item = item.lower() if item.isupper() else upperfy(item)
            return super(DynaBox, self).__getattr__(n_item, *args, **kwargs)

    @evaluate_lazy_format
    def __getitem__(self, item, *args, **kwargs):
        try:
            return super(DynaBox, self).__getitem__(item, *args, **kwargs)
        except (AttributeError, KeyError):
            n_item = item.lower() if item.isupper() else upperfy(item)
            return super(DynaBox, self).__getitem__(n_item, *args, **kwargs)

    def __copy__(self):
        return self.__class__(
            super(Box, self).copy(),
            box_settings=self._box_config.get("box_settings"),
        )

    def copy(self):
        return self.__class__(
            super(Box, self).copy(),
            box_settings=self._box_config.get("box_settings"),
        )

    def _case_insensitive_get(self, item, default=None):
        """adds a bit of overhead but allows case insensitive get
        See issue: #486
        """
        lower_self = {k.casefold(): v for k, v in self.items()}
        return lower_self.get(item.casefold(), default)

    @evaluate_lazy_format
    def get(self, item, default=None, *args, **kwargs):
        if item not in self:  # toggle case
            item = item.lower() if item.isupper() else upperfy(item)
        value = super(DynaBox, self).get(item, empty, *args, **kwargs)
        if value is empty:
            # see Issue: #486
            return self._case_insensitive_get(item, default)
        return value

    def __dir__(self):
        keys = list(self.keys())
        reserved = [
            item[0]
            for item in inspect.getmembers(DynaBox)
            if not item[0].startswith("__")
        ]
        return (
            keys
            + [k.lower() for k in keys]
            + [k.upper() for k in keys]
            + reserved
        )